1. Field of the Invention
The present invention relates to dental wedges that may be used in the restoration of a decayed portion of a tooth.
2. Description of the Related Art
Dental cavities that have spread to the dentin or have undergone cavitation are typically treated by removing the decayed portion of the tooth and thereafter filling the missing tooth structure with a restorative material such as silver (amalgam), white (resin), porcelain, or gold. Cavities that are located adjacent to neighboring teeth are called interproximal cavities.
When treating interproximal cavities, the dentist first removes the decayed portion of the side of the tooth. In order to properly deposit the restorative material on the side of the tooth without undesired leaking of the restorative material beyond the side of the tooth, the dentist places a dental matrix around at least a portion of the tooth. The dental matrix may be a metallic or plastic strip, and when the matrix is placed around at least a portion of the tooth, the matrix acts as a form for the desired shape of the restored tooth.
One or more dental wedges may be used when treating interproximal cavities. Various dental wedges are shown in U.S. Pat. Nos. 7,223,101, 6,890,176, 6,761,562, 6,482,007, 6,435,874, 6,425,760, 6,234,792, 6,074,210, 5,743,738, 5,527,181, 5,104,317, 4,468,199, 4,337,041, 4,259,070 and D439,667, and U.S. Patent Application Publication Nos. 2007/0254263 and 2003/0113688. Historically, traditional dental wedges have been used to perform two functions, the first and most important is to press the dental matrix (sectional or 360 degree wrap) against the tooth so that matrix seals the tooth and keeps the filling material inside of the desired space. The second purpose is to separate the teeth so that when the matrix is removed after placing and hardening the filling material, the gap that is formed when the matrix is removed is mitigated as the teeth “spring” back together and close the gap that was present when the matrix was removed, typically about a two mil thickness.
Wedging devices are typically inserted from the facial or lingual direction to stabilize the matrix, press the matrix, improve the adaptation of the matrix against the tooth surface, to lightly or aggressively separate the tooth to compensate for the thickness of the matrix, and to seal the gingival margin to keep excess fluid from squirting past the interface thru a gap, to discourage body fluids from entering the cavity space thru the interface, and to apply pressure to the gingiva to control bleeding.
Because the new composite dental filling materials are more delicate than silver amalgam and cannot be packed as aggressively, it is common today to see that many posterior and anterior composite fillings have poor contacts that allow food impaction, etc. Additionally, the typical triangular shape of most wedges press against the matrix at the top corner, causing a flat spot in the filling that becomes a harbor for food impaction and bacterial accumulation. Concave surfaces in the interproximal area create an uncleansable area as the floss arcs across the flat spot or concavity. In addition, the papilla or gum triangle that is present in healthy situations can become blunted without the static tension of a full, rounded interproximal tooth shape (see, Clark, “Restoratively Driven Papilla Regeneration: Correcting the Dreaded Black Triangle”, Canadian Journal of Restorative Dentistry and Prosthondontics, August 2008). The ensuing “Black Triangle” can further compromise the interproximal health with plaque accumulation and food impaction along with esthetic compromise, as the dark spaces between teeth are considered to be unaesthetic and prematurely ages the smile.
Some dental wedges, such as that shown in U.S. Pat. No. 7,223,101, along with others, have a slightly concave gingival surface that does not nearly address the problem of the wedge “riding up” into the embrasure space resulting in the above mentioned concavity in the resultant filling shape and or black triangle issue, as the arc is x angle or may be 5% hollow. The very slight gingival concavity, is so minimal that it does little to allow the wedge to seat itself deeply into the gum area and therefore does not address the aforementioned problems that occur in some clinical situations such as deeper decay or hypertrophic gums (oversized interdental gum triangle).
The wedge of U.S. Patent Application Publication No. 2007/0254263 makes advancement in this problem with the wedge that is in essence hollow in the gum area which allows the wedge to be placed deeper into the gum area because it has space for the “triangle” of gum tissue that pushes other solid wedges “up” or “superiorly” against the matrix to create the problems heretofore mentioned. There are however five problems with the wedge of US 2007/0254263. First, the wedge's design is so flimsy that it does not create enough pressure to separate the teeth and is therefore marketed with the separate V3 and V ring separators. The disadvantage with this system is that the wedge cannot be used alone; necessitating the additional time required to place the separating ring in addition to placing the wedge. This becomes a more serious problem for the anterior teeth where the separating rings are typically not used because the shape of the front teeth is different than the posterior teeth. For anterior teeth, the dentist becomes limited to using only the wedge which, in the case of the wedge of US 2007/0254263, does very little wedging.
The second problem with the wedge of US 2007/0254263 is that the top angle or corner is pointed which can put unfavorable pressure on the matrix and create a flat spot on the matrix and the resultant filling shape.
The third problem is that the wedge of US 2007/0254263 is opaque, not allowing light transmission. Most composite restorations today require photo polymerization to harden and cure the filling material. It is an advantage to have both matrix and wedge that allows the curing light to transmit light through their structures without impediment.
The fourth problem is that the wedge of US 2007/0254263 along with most other wedges must be inserted from one side of the teeth or the other side, and that to be thin enough to pass through the narrow space disallows a wide and broad pressure to adequately press the matrix against the tooth in the outer curved area.
Another problem is that of translucency to allow the photons of the curing light to reach the composite material to initiate and complete the photopolymerization. An opaque wedge blocks any lateral transmission of light. That is important whenever a non metal, translucent matrix is used. A second consideration of the wedge is luminescence. A dark material will provide less luminescence than a white material. It may be of an advantage for an opaque reflectant wedge or a two part translucent/opaque wedge to indeed block the light, once the wedge portion engaging the tooth has extended beyond (below or in the gingival direction) of the termination or gingival margin of the filling; where it will block the travel of the unused photons, then luminesce to essentially reflect the light back toward the filling instead of wasting the photon light energy that is radiating in the gingival direction.
Furthermore, traditional dental wedges have historically had a poorly designed grip area. In addition, the common practice of first partially inserting the wedge with a typical grip with the tips of the pliers, meeting resistance, releasing the wedge, rotating the pliers to push against the wedge with the larger flat handle of the pliers. Worsening the problem of the poorly designed end of the wedge is that all plastic wedges to date have a vestige on the outer end surface that disadvantages the dentist further encouraging the back or handle end of the pliers to slip off the outer end surface and traumatize the gums or tooth in addition to requiring the dentist to waste time and energy.
During insertion, the dental wedge can inadvertently rotate without visual cues to the dentist because once the wedge is inserted the handle is the only visible portion of the wedge.
In addition, all previous wedges from top view were either concave in the areas were the wedge engages the teeth or flat (wedge shaped). The cervical or gum area of the teeth, especially bicuspids and molars can have a slight or significant concavity that is described as either fluting or a furcation. It is extremely common in these instances for excess of filling material to squirt through the gap present as the dental matrix arcs across the concavity as the matrix wants to remain flat as it cuts the shortest distance across two prominences. This is referred to as an overhang or excess of filling material and often results in chronically inflamed gum tissues and potential gum disease and aggravation to patient as the floss shreds and snags.
Thus, there is a need for improved dental wedges that may be used in the restoration of a decayed portion of a tooth.